Gripper-arm



L. J. WARNER.

GRIPPER ARM.

APPLICATION FILED JAN-24, 1920.

1 387,026 Patented Aug. 9, 1921.

Fig. 1.

IN VEN TUH LEROY J. WARNER, 0E FOSTOBIA, OHIO.

GRIPPER-ARM.

Specification of Letters Patent.

Patented Aug. 9, 1821.

Application filed January 24,1320. Serial No. 353,895.

To (ZZZ-whom it may concern:

Be itknown that I, LEROY J. lVAnNnn, a citizen of the United States, and a resident of Fostoria, in the county of Seneca and State of Ohio, have inventedv a certain new and useful Gripper-Arm; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the characters of reference marked thereon, which form a part of this specification. v

This invention relates to gripper-arms for use in connection with printing presses, and

particularly with those of the Gordon job or flat platen type, to hold an impression sheet to the platen during the making of an impression and the initial movement ofthe platen away from the form, whereby the sheet is drawn away from the inked face of the form upon the recedingmovement of the platen. v

In the use of gripper-arms of this character, considerable difliculty is experienced by reason of the gripper-arms not bearing with sufficient force against the platen to resist to any considerable extent the withdrawal of a sheet-from therebetween so that sheets frequently remain sticking to the form after theplaten has receded, and

particularly so if the form is heavily inked, and are 'then caused to-wind on the inking rolls as they pass over the form in the next inking operation. p

The object-of my invention is the provision of a gripper-arm of the class described which will overcome the objections incident, so far as I am aware, to those formerly used, by reason of its pressure against the platen being uniformly increased or augmented throughout its length during the last portion of the impression stroke, the period,

of the impression and the initial portion of the retaining or back stroke of the platen,

which pressure is occasioned by the cooperation of the chase with the gripper-arm.

A further object of my invention is the provision of an. improved gripper finger for use on gripper-arms of the classy described.

The invention is fully described in the following specification, and while, in its broader aspects, it is capable of embodiment in numerous forms, a preferred embodiment thereof is illustrated in the accompanying on awlngs, 1n wh1ch,

Figure 1 1s a face view of a planten, with gripper-arms embodying the invention associated therewith and in sheet holding position. Fig. 2 is a side edge elevation of a gripper-arm embodying the invention. Fig. 3. 1s an enlarged perspective view thereor, with a gripper-finger mounted thereon. Fig. 4: is an enlarged cross-section of the grippenarm taken on the line 4,4t in Fig. 1, and Fig. 5 is an enlarged perspective view ofone of the gripper-fingers removed from the gripper-arm.

, Referring tothe drawings, ldesignates a grippenarm and 2 a yieldlng facing strip therefor, which ispreferably of spring strap metal. This facing strip s fixed at its inner end to the chase coa'ctingside of the gr pper-arm i, ad acent to theinner end 7 thereof, as at 3, and. extends lengthwise of the gripper arm,'bowing outwardly from its point-of attachment thereto and having its free end in sliding contact with the arm 1, 4

or acentto its outer end, preferably. within a guiding channel' i therein. The bow of of the facing strip 2 is preferably drawn in- 5 wardly intermediate its. endsto have contact with the face of the gripper-arm, as shownat 2 ,'thus forming the strip with. two

successively bowedportions instead ofone.

This feature is not important, however, so

.far as they function of -the gripper-arm is concerned, and'the strip may haveany number ofbowefd port ons. I 1 c The arm 11S lntended to bear at itslouter or fiat side against the face of a platen 5,

with which associated, in position for the arm or for gripper fingers 6 thereon tocoact I with a sheet 7 on'the platen to hold: it in vided with a flattened enlargement o'rhead 8 forclamping to a rocking member 9 at the position as is customary with. gripper-arms of this character and as is well understood in the art. The inner end of the arm 1 is prolower or inner edge of the platen 5, and this 7 head is preferably provided with a flange or lip l0at one. edge for seating in a registers ing groove 11 in the rocker member9. The V I head 8 is also provided with a hole 12 through which a securing bolt 13 may be inserted. This bolt is intended. to pass through a longitudinal slot 4 in the rocker member, as is customary with devices of this character, thus adapting the gripper arm to 110.

be adjusted longitudinally of the rocker member as the work to be performed may require.

It is evident that the outwardly bowed portions of the yielding spring facing strip 2, which is disposed at the outer side of the gripper-arm with respect to the platen, comes in contact with the registering portion of the form holding chase before the platen has moved completely to printing position so that a further movement of the platen toward the form will cause the facing strip 2 to be compressed against the arm 1, thus causing the chase to cooperate with the strip 2 to exert a sheet holding pressure on the gripper-arm 1. This pressure as is apparent, continues until the platen and gripper-arm 1 have receded a sufficient distance from the form or chase 011 the back or returned stroke of the platen to withdraw the stri p 2 from contact with the chase, thus continuing the increased or augmented pressure of the gripper-arm on the engaged sheet until the latter has been drawn away from the inked surface of the form during the back stroke of the platen. It is found in practice that the increased and prolonged pressure which is uniformly exerted on the gripper-arm throughout its length during the receding of the platen from the form after a printing operation, is such as to cause a gripping of the impression sheet with sufficient force to effect its withdrawal from the form, even though the latter is heavily inked, thereby preventing the sheet from sticking to the form and being wound on the inking rolls during the next inking operation, which is a fault very frequently encountered in connection with the use of gripper-arms of the type customarily used.

Itis found that when the inking rolls are provided at the outer side thereof with a distributing roll, as is frequently the case in presses of the character described, the outward projection of the distributing roll will cause it to coact with the facing strip as the inking rolls pass downward over the form during a receding movement of the platen, unless the facing strip 2 is bowed inwardly at the point where the distributing roll would otherwise have contact therewith. The primary purpose therefore, for in wardly bowing the strip is to provide a clearancespace for the distributing roll of an inking roll sheet as the latter passes downward over the form during the receding or back stroke of the platen.

The gripper-arm 1 may be provided with one or more laterally extending sheet gripping fingers which have sliding gripping coaction with the gripper-arm for adjustment lengthwise thereof. The gripper-finger which I have preferably employed for this purpose is provided at oneend with upwardly and inwardly turned ears 15 and in slightly spaced relation thereto lengthwise of the finger with an ear 16 struck up from the linger and adapted to cooperate with the ears 15 to slidingly embrace the gripper-arm. The outer end of the gripperlinger is provided with two transversely spaced ears 1'? bent upward and inwardly over the finger end to form hooks with which an end of a rubber band 18 extending across from the gripper-finger of one arm to the gripper-finger of another arm may have looped engagement. If the space between the two portions of the form with which the elastic band is to register, is narrow, the band may be looped over a single hook 17 at each end thereof, or if the space is of suffieient width the band may be looped over both hooks 17 of each of the connected fingers.

I wish it understood that my invention is not limited to any specific construction, arrangement or form of the parts as it is capable of numerous modifications and changes without departing from the spirit of the claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is, I

A gripper arm of the class described, comprising a bar having its back face longitudi nally grooved near its inner and outer ends and a spring metal facing strip fixedly mounted at one end in one groove and having its other end slidingly mounted in the other groove, the faclng strip forming a plurality of undulations lengthwise thereof with the connecting portions of the undulations bearing against the bar in sliding contact therewith and with the outwardly bowed portions thereof projecting laterally of the bar.

In testimony whereof I have hereunto signed my name to this specification.

LEROY J. WARNER lOO 

